反应详情

To a solution of 3-bromo-5-ethoxypyridine (53 g, 262 mmol) in DCM (600 mL) at 0° C. was slowly added m-CPBA (67.9 g, 393 mmol) over 30 min. After the resulting solution was stirred for 15 h, the mixture was washed with Na2S2O3 solution and extracted with DCM (600 mL×2). The combined organic layer was washed with saturated NaHCO3 (300 mL), brine (300 mL), dried over Na2SO4, filtered, and concentrated to give 3-bromo-5-ethoxypyridine-1-oxide (40 g, 165 mmol, 63% yield): 1HNMR (400 MHz, CD3OD) δ 8.19-8.18 (m, 1H), 8.08-8.07 (m, 1H), 7.50-7.49 (m, 1H), 4.17-4.15 (d, J=8.8 Hz, 2H), 1.43 (t, J=7.0 Hz, 3H); ES-LCMS m/z 217 (M+H).

1. customat 0° C.
2. customover 30 min
3. washthe mixture was washed with Na2S2O3 solution
4. extractionextracted with DCM (600 mL×2)
5. washThe combined organic layer was washed with saturated NaHCO3 (300 mL), brine (300 mL)
6. dry with materialdried over Na2SO4
7. filtrationfiltered
8. concentrationconcentrated